Definition of Computer Virus Please!?

Question

the answer is for preparing for an examination and therefore,scholarly answers are most welcome.

Answer 1

A computer virus is a self-replicating program containing code that explicitly copies itself and can "infect" other programs by modifying them or their environment such that a call to an infected program implies a call to a (possibly evolved) copy of the virus.
http://www.msun.edu/infotech/its/how/glossary/c.htm

A software program capable of reproducing itself and usually capable of causing great harm to files or other programs on the same computer; "a true virus cannot spread to another computer without human assistance"
http://wordnet.princeton.edu/perl/webwn

In computer security technology, a virus is a self-replicating program that spreads by inserting copies of itself into other executable code or documents. Thus, a computer virus behaves in a way similar to a biological virus, which spreads by inserting itself into living cells. Extending the analogy, the insertion of the virus into a program is termed infection, and the infected file (or executable code that is not part of a file) is called a host.
http://en.wikipedia.org/wiki/Computer_virus

* 5 different types of computer viruses = Trojan Horse, Worms, Logic Bomb, Time Bomb, and Macro Virus.

Macro virus is viral program written using Word's or Excel's macro programming language. These viruses, come attached to a Word document without your knowledge. When you open the Word document, the virus program executes and performs what its programmed to do.
http://www.hawaii.edu/maui/computing/viruses/virusdef.html

A Trojan horse is a program in which malicious or harmful code is contained inside apparently harmless programming or data in such a way that it can get control and do its chosen form of damage, such as ruining the file allocation table or hard disk.
http://www.antispam.org.sg/glossary.html

A worm replicate themselves but do not alter files. The main difference is that worms reside in memory and usually remain unnoticed until the rate of replication reduces system resources to the point that it becomes noticeable.
http://www.techdirectcomputers.com/Encyclopedia.htm

A computer program that is triggered under certain conditions specific to the requirements set forth by the programmers of the logic bomb. Trigger conditions may be a date or time combination. When the Logic Bomb is triggered, it then makes copies of itself, "exploding," until the entire system is locked.
http://www.nve.vt.edu/cias/Resources/glossary.htm

Time Bomb is a computer program designed to cause damage within a computer system at a specified time.
http://www.indiainfoline.com/bisc/acct.html

Answer 2

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Answer 3

COMPUTER VIRUS typically are a short program designed to disperse copies of itself to other computers and disrupt those computers' normal operations. A computer virus usually attaches or inserts itself to or in an executable file or the boot sector (the area that contains the first instructions executed by a computer when it is started or restarted) of a disk; those that infect both files and boot records are called bimodal viruses. Although some viruses are merely disruptive, others can destroy or corrupt data or cause an operating system or applications program to malfunction. Computer viruses are spread via floppy disks, networks, or on-line services. Several thousand computer viruses are known, and on average three to five new strains are discovered every day.

A distinction should be made between a virus—which must attach itself of another program to be transmitted—and a bomb, a worm, and a Trojan horse. A bomb is a program that resides silently in a computer's memory until it is triggered by a specific condition, such as a date. A worm is a destructive program that propagates itself over a network, reproducing as it goes. A Trojan horse is a malicious program that passes itself off as a benign application; it cannot reproduce itself and, like a virus, must be distributed by diskette or electronic mail.

When you listen to the news, you hear about many different forms of electronic infection. The most common are:

Viruses - A virus is a small piece of software that piggybacks on real programs. For example, a virus might attach itself to a program such as a spreadsheet program. Each time the spreadsheet program runs, the virus runs, too, and it has the chance to reproduce (by attaching to other programs) or wreak havoc.

E-mail viruses - An e-mail virus moves around in e-mail messages, and usually replicates itself by automatically mailing itself to dozens of people in the victim's e-mail address book.

Worms - A worm is a small piece of software that uses computer networks and security holes to replicate itself. A copy of the worm scans the network for another machine that has a specific security hole. It copies itself to the new machine using the security hole, and then starts replicating from there, as well.

Trojan horses - A Trojan horse is simply a computer program. The program claims to do one thing (it may claim to be a game) but instead does damage when you run it (it may erase your hard disk). Trojan horses have no way to replicate automatically.
Computer viruses are called viruses because they share some of the traits of biological viruses. A computer virus passes from computer to computer like a biological virus passes from person to person.

There are similarities at a deeper level, as well. A biological virus is not a living thing. A virus is a fragment of DNA inside a protective jacket. Unlike a cell, a virus has no way to do anything or to reproduce by itself -- it is not alive. Instead, a biological virus must inject its DNA into a cell. The viral DNA then uses the cell's existing machinery to reproduce itself. In some cases, the cell fills with new viral particles until it bursts, releasing the virus. In other cases, the new virus particles bud off the cell one at a time, and the cell remains alive.

A computer virus shares some of these traits. A computer virus must piggyback on top of some other program or document in order to get executed. Once it is running, it is then able to infect other programs or documents. Obviously, the analogy between computer and biological viruses stretches things a bit, but there are enough similarities that the name sticks.

In short definition you can write:
Computer virus is a software program capable of reproducing itself and usually capable of causing great harm to files or other programs on the same computer; "a true virus cannot spread to another computer without human assistance".

Full marks!

Answer 4

In computer security technology, a virus is a self-replicating program that spreads by inserting copies of itself into other executable code or documents (for a complete definition: see below). Thus, a computer virus behaves in a way similar to a biological virus, which spreads by inserting itself into living cells. Extending the analogy, the insertion of the virus into a program is termed infection, and the infected file (or executable code that is not part of a file) is called a host

Answer 5

computer virus-A computer program that is designed to replicate itself by copying itself into the other programs stored in a computer. It may be benign or have a negative effect, such as causing a program to operate incorrectly or corrupting a computer's memory.

Answer 6

probability-free mode with networking. keep urgent F8 because the computer restarts until eventually you word the alternative demonstrate. this assist you to get entry to the web with none virus procedure operating and also you ought to be able to replace the antivirus and run an total equipment test.